Neural Signatures of Autism Spectrum Disorders: Insights into Brain Network Dynamics

Abstract

Neuroimaging investigations of autism spectrum disorders (ASDs) have advanced our understanding of atypical brain function and structure, and have recently converged on a model of altered network-level connectivity. Traditional task-based functional magnetic resonance imaging (MRI) and volume-based structural MRI studies have identified widespread atypicalities in brain regions involved in social behavior and other core ASD-related behavioral deficits. More recent advances in MR-neuroimaging methods allow for quantification of brain connectivity using diffusion tensor imaging, functional connectivity, and graph theoretic methods. These newer techniques have moved the field toward a systems-level understanding of ASD etiology, integrating functional and structural measures across distal brain regions. Neuroimaging findings in ASD as a whole have been mixed and at times contradictory, likely due to the vast genetic and phenotypic heterogeneity characteristic of the disorder. Future longitudinal studies of brain development will be crucial to yield insights into mechanisms of disease etiology in ASD sub-populations. Advances in neuroimaging methods and large-scale collaborations will also allow for an integrated approach linking neuroimaging, genetics, and phenotypic data.

Identification of segregated regions in the functional brain connectome of autistic patients by a combination of fuzzy spectral clustering and entropy analysis

“…Therefore, our results further corroborate the theoretical view that ASD, along with other major psychiatric disorders, is a brain network disorder in which the balance between functional integration and the segregation of large-scale neurocognitive networks is altered. 12,42,43 The biological mechanisms that generate the modularitybased alterations in functional connectivity in patients with ASD observed in our study remain unknown. It has been proposed that ASD, as a developmental disconnection syndrome, is associated with abnormalities in anatomic connectivity between specialized brain regions.…”

Face processing in autism spectrum disorders: From brain regions to brain networks

“…Functional task-related correlations have also been found between face sensitive cortical areas (Miyahara et al, 2013) in the NT brain. There is a growing literature on brain connectivity in autism, pointing to patterns of both hyper- and hypo-connectivity during task and resting states (see Uddin et al, 2013; Kana & Just, 2011; Muller et al, 2011; Vissers et al, 2011; Hernandez et al, 2014 for review). Here we focus specifically on research describing functional and effective connectivity within networks relevant for face processing (Table 5).…”

Neuroimaging in autism spectrum disorder: brain structure and function across the lifespan

“…111 However, fi ndings from most studies have continued to support the broad notion that, overall, individuals with ASD have poorer connectivity in regions spanning long distances in the brain than do typical controls, whereas connectivity seems to be increased in local circuits. 92,[112][113][114] Furthermore, important properties of network connectivity seem to be altered in ASD; for example, the development of domain-specifi c function modules is reduced. 115,116 Although local connectivity within central hubs or rich clubs (ie, high-degree nodes that are more densely connected among themselves than nodes of a lower degree) seems to be increased, 117 the hub organisation is altered across the brain.…”